Passengers must buy their own tickets before boarding any local and regional transport service* operated by ÖBB-Personenverkehr AG. This means that you must have a valid ticket before passing through the barrier and/or before starting your journey. If you are found to be travelling without a valid ticket, you will be issued with a penalty fare. It makes no difference if you did not have time to buy a ticket or if you have lost it.
If the train attendant issues a penalty fare, this can be paid immediately in cash. If payment is not made immediately, an additional penalty will be issued for later payment, which will increase the amount of the penalty fare overall. The penalty must be paid within 14 days.
* Local trains include: REX, R, CJX, S-Bahn